.Net C#: Compress / Decompress Methods

Utility Methods for data compression and data decompress.

using System.IO;
using System.IO.Compression;

    public static byte[] Compress(byte[] bytes)
    {
      byte [] retValue;
      using (MemoryStream stream = new MemoryStream())
      {
        using (GZipStream zipStream = new GZipStream(stream, CompressionMode.Compress, true))
        {
          zipStream.Write(bytes, 0, bytes.Length);
          retValue = stream.ToArray();
          zipStream.Close();
          stream.Close();
        }        
      }
      return retValue;
    }


    public static byte[] Decompress(byte[] bytes)
    {
      byte[] retValue; 
      using (MemoryStream stream = new MemoryStream())
      {
        using (GZipStream zipStream = new GZipStream(new MemoryStream(bytes), CompressionMode.Decompress, true))
        {
          byte[] buffer = new byte[4096];
          int size;
          while (true)
          {
            size = zipStream.Read(buffer, 0, buffer.Length);
            if (size > 0)
              stream.Write(buffer, 0, size);
            else
              break;
          }
          zipStream.Close();
          retValue = stream.ToArray();
          stream.Dispose();
          zipStream.Dispose();
          return retValue;
        }
      }